1. Field of the Invention
The present invention relates to novel Spergualin-related compounds, and a process for producing the same. More particularly, the invention relates to Spergualin-related compounds of the formula: ##STR2## (wherein R.sub.1 is a lower alkylene group which may be substituted by a hydroxymethyl group; X is a hydrogen atom or a halogen atom; m and n are each 0 or an integer of 1 to 5) and salts thereof, as well as a process for producing phenylene group containing Spergualin-related compounds of formula (I) and salts thereof characterized by removing the protecting groups from a protected Spergualin-related compound of the formula: ##STR3## (wherein R'.sub.1 is a lower alkylene group which may be substituted by a hydroxymethyl group, the hydroxyl group of which may be protected; R.sub.2 is an amino protecting group; R.sub.3 is a protected amino group; X, m and n are the same as defined above).
2. Description of the Prior Art
Spergualin is a compound that was isolated from a culture filtrate of a Spergualin producing microorganism of the genus Bacillus by Umezawa, one of the inventors of the present invention, and others. Spergualin has the following structure: ##STR4##
Spergualin has the ability to inhibit the growth of Gram-positive and Gram-negative microorganisms. It has been proved to have significant antineoplastic effects on experiments on the curing of mouse leukemia L1210, leukemia EL-4, and Ehrlich carcinoma, Sarcoma 180. For these reasons, Spergualin is considered to be a promising antineoplastic agent [see Japanese Patent Kokai (Laid-open) No. 48957/1982].
Umezawa et al. also found that Spergualin derivatives such as acylated compounds at 15-position have similar effects [Japanese Patent Kokai (Laid-open) Nos. 185254/1982 and 62152/1983].
However, Spergualin and its known derivatives are unstable in an aqueous solution.